Bailway-tbaffic-contktfliing apparatus



F. H. NICHOLSON.

RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLICATION FILED JAN. 24,1917.

Patented Sept. 30, 1919.

JINVENTOR.

BY Q z. I: f Ah, ATTORNEY;

ZSTNESSES:

nut!

UNITED sTA'rEs PATENT OFFICE.

FRANK H. NICHOLSON, OF WEST'HAVEN, CONNECTICUT.

RAILWAY-TRAFFIC-COIITROLLING APPARATUS.

Specification of Letters Patent.

Patented Sept. 30, 1919.

Application filed January 2-1, 1917. Serial No. 144,159.

giving indications to the driversof cars or trains passing along the railway. More particularly my invention relates tomeans for. varying the intensity of illumination of such lan ips,to provide fonabrilhant illumination or :r'cbinparatively weak illumination, depending upon the circumstances under which the lamp is used.

' For example, when the lamp is employed for giving indications both in daylight and darkness, the lamp must during daylight be illuminated at such intensity as to be clearly visible during the brightest sunlight and under the Worst conditions of relative position of the sun and the signal, namely, when the signal is directly between the observer land the sun; but it is undesirable that this high intensity of illumination be maintained at night, because the light from the lamp would then be dazzling to the observer and the" observation at frequent intervals of a succession of signals comprising such lamps would have an undesirable physiological effect on the observer. It is therefore desirable that the lamps in such signals be illuminated at a high intensity for daylight indications and at a lowerintensity for indications during darkness.

One feature of myinvention is the pro vision of means for causing the illumination of the lamps in such signals at one intensity for indications under certain conditions and at a lower intensity for indications under other conditions.

I will describe one form of apparatus embodying my invention and will then point out the novel features thereof in claims.

The accompanying drawing is a view showing diagrammatically one form of apparatus embodying my invention.

Referring now to the drawing, the refer ence character R designates the track rails of a railway adjacent which is located a signal S comprising, as here shown, three electric incandescent lamps L L and L which lamps when illuminated are adapted to indicate respectively Proceed, Proceed with caution,-and Stop. I will assume that these lamps are employed for giving indications both in daylight and in darkness,

and that therefore illumination of the lamps at one intensity for daylight purposes, and at a lower. intensity for conditions of darkness, is desirable, The light from these lamps is usually concentrated into a beam of substantially parallel rays by means of a lens in front of each lamp, and the three beams are usually caused to differ in color by colored glasses located in suchbeams, but these lenses and colored glasses are omitted to simplify the drawing. i

The three lamps L L and L are, as here shown, connected in multiple and are energized from a secondary 8 of a transformer T, the circuits for these lamps being apparent from the drawing. It is understood that the circuits for the individual lamps L L and L are controlled by other means depending on the conditions of trafiic along the railway, but inasmuch as such means constitute no part of my invention they are omitted from the drawing for the purpose of simplicity. The primary winding p of transformer T is energized from the secondary 6 of another transformer 6 the primary 6 of which is connected with a suitable source of alternating current (not shown). The circuit for primary p of transformer T is from the lower terminal of secondary 6* of transformer 6 through wires 7, 8 and 9, primary p, wires 10, 11 and 12, to substantially the middle point of the secondary winding 6". It will be obvious, therefore, that secondary p is energized at all times when alternating current is supplied to the primary of transformer 6.

It will be noted that the primary 7) and the secondary 8 of transformer T are located on different parts of a core 2 of magnetizable material, the portion of this core on which these windings are placed constituting a closed magnetic circuit, so that if no other means were provided the greater pm: of the magnetic flux created by the primary 7? would pass through the secondary 8 and so I generate a certain' voltage in the secondary, depending chiefly" on the voltage applled to-"the primary and the ratioi between the number of turns-in theprimary and the 5 .-secondary.'v

The transformer T is provided with means.

-- for varying the roportion of. the magnetic flux created by t eprimary p "which passes through the secondary s. -As here shown,;

this means comprises'two legs 3 and 3 in tegral with the core 2 and connected there? with at the opposite endsof the primary winding p. 4 is a-member of magnetizable ,material movable toward and away from the. extremities of the legs 3 and 3. It will be apparent that when the member 4 issubstantially in engagement with the legs 3 and 3, a certain portion ofthe magnetic flux created by the primary p will pass through the member 4 and so will be shunted from' the secondary 8, thus reducing the proportion. of the primary flux which passes through the secondary 8 and so reducing the" voltage applied to the lamps of signal S. The. member 4 is biased by gravity or otherwise to a position wherein it rests on fixed stops 5, 5. When in such position the member is at such distance from the legs 3, 3 that it is not attracted to these legs by the magnetic flux created by the primary 2,

and that it diverts substantially none of the primary fiux from the secondary when transformer is under full load. I

Suitable means are provided for moving the member 4 into engagement with the legs 3 and 3". As here shown, this means c0mprises a winding 18 on the member 4, which,

winding is energized with alternating cur rent of one instantaneous polarity or, an-

40 other with respect to the current in the -transformer primary p. In the arrangement here shown, one terminal 17 of winding 18 is connected with the middle point of the secondary 6 of transformer 6 by means of wires 11 and 12, and the other terminal 16 of winding 18 is connected with one end or the other of transformer secondary (3 through the medium of wires 14 and 15 and a manually operable switch 13. -This switch 13 when swung to the left engageswith a'bontact 13, which is connected with the lower terminal of the secondary 6 and when swung to the rightengages with a 'rent of such instantaneous polar-it I respect to the current in primary 1) t atthe fluxes created by these two windings will cooperate-to attract member-4 to the legs the of my invention.

be illuminated at their full intensity, as is desirable for daylight conditions. If new switch 13 is swung to the left, the winding 18 on member 4 will be energized with cur-, I with '3 and 3'2 Switch 13 may. now be opened i and the member 4: will remain'in its attracted position due to the flux-created by theprimary winding p. -"A- certain proa portion of the primary flux is now; diverted zthrough member 4 and so is shunted from: secondary '8, thus reducing the voltage applied tothe lamps of signal S to the desired -degree for'eonditions of darkness.

it isdesiredto return the lamps S to the full intensity of illumination, the switch-I13 I isswung to the right, thus energizing winding l8-w1th current ofthe-reverse instantaneous polarity with respect to the current in primary p, so that member 4: is then re-v pelled from the core of transformer T and I 1 shown in the drawing; 'The shunt path for so returns to the position in which it"flis the primary flux being'then removed, the

- voltage applied to the lamps of signal i returned to its original value.

The control switch 13 is preferablylocated in a tower or other inclosure where.

it may readily be reached by the operator who is to control the intensity. of the illumination of the lamps. It is understood that although only one signal S is shown 00 in the drawing, any numberof signals may I be controlled by the one control switch 13,

.each such signal being provided with a 1 transformer T, each of which transformers is connected with the line wires-14, l1 and 8, in the same manner as is the transformer T shown in the drawing. I I 1 Although I have herein shown and de-. I scribed only one form of railway traflic controlling apparatus embodyin my invention, it is understood that various changes and modifications may 'be made therein within the scope of the appended claims without departing from the spirit and scope Having thus described my invention, what I claim is: Y

1. In combination, a signal comprising an electric lamp, a source of alternating current, a transformer whose primary is en- 12o ergized from said source and whose second? ary is connected with said lamp, a member of magnetizable material movable toward and away from the core of said transformer to shunt from the secondary a portion of the magnetic flux created by the primary, a winding on said member, and means for energizing said winding with alternating current of one instantaneous polarity or another with respect to the current in the so When i primary whereby said member will be attracted to or repelled from the transformer core.

2. In combination, a signal comprising an electric lamp, a source of alternating current, a transformer whose primary is energized from said source and Whose secondary is connected with said lamp, a member of magnetizable material movable toward and away from the core of said transformer to shunt from the secondary a portion of the magnetic flux created by the primary, said member being biased away from said core to such position that there is substantially no magnetic leakage therethrough when the transformer is under full load, and means for moving said member against its bias into substantial contact with said core and for repelling said member from said position, the member when in contact with the core being retained in such position by the primary flux flowing therein.

3. In combination, a signal comprising an electric lamp, a source of alternating current, a transformer whose primary is energized from said source and whose secondary is connected with said lamp, a anember of magnetizable material movable toward and away from the core of said transformer to shunt from the secondary a portion of the magnetic flux created by the primary, said member being biased away from the core to such position that it not attracted to the core by the primary flux inthe core, a winding on said member, "means for momentarily energizing said winding from said source with current of one instantaneous polarity with respect to the prinrary' current whereby said memoer is attracted substantially into contact with the core, the member being retained in in presence of two witnesses.

such attracted position by the primary flux flowing therein, and means for momentarily energizing said winding from said source with current of the opposite instantaneous polarity with respect to the primary current whereby'the member is then repelled from said core.

4. In combination, a signal comprising an electric lamp, a source of alternating current, a transformer whose primary is energized from said source and whose secondary is connected with said lamp, a member of magnetizable material movable toward and away from the core of said transformer to shunt from the secondary a portion of the magnetic flux created by the primary, said member being biased away from the core to a position in which it cannot be moved to the core by the primary flux alone in the core, a winding on said member, means for momentarily energizing said winding from a source of alternating currentwith current of one instantaneous polarity with respect to the primary current whereby said member is moved by magnetic attraction substantially into contact with the core, the member being retained in such attracted position by the primary flux flowing therein, and means for momentarily energizing said winding from a source of alternating current with current of the .opposite instantaneous polarity with respect to the primary current whereby the member is then repeiled from said core.

In testimony whereof I affix my signature FRANK H. NICHOLSON.

Witnesses WILLIAM E. DRURY, FRANK A. BEAOEKADOR. 

